<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .login-box {
            height: 150px;
            width: 200px;
            padding: 50px;
            position: absolute;
            top: 50%;
            left: 50%;
            margin-top: -100px;
            margin-left: -100px;

            background-color: aquamarine;


        }

        input {
            margin-bottom: 20px;
        }

        button {
            position: absolute;
            display: inline-block;
            bottom: 30px;
            left: 80px;
            background-color: chartreuse;
            width: 150px;
        }
    </style>
</head>

<body>
    <form action="/login" method="post">
        <div class="login-box">
            账号：<input type="text" name="username" id=""><br />
            密码：<input type="password" name="pwd" id=""><br />
            <button>登录</button>
        </div>
    </form>
</body>

</html>